This adaptation of Alan Jay Lerner and Frederick Lowe's Broadway musicalisation of the King Arthur legend (based on TH White's The Once and Future King) turned out to be one of the last big budget movie musicals of the Sixties, and was also the last film produced by the legendary Jack Warner. It was rewarded with Oscars for Best Sets and Costumes, as well as Best Music Score Adaptation.

As ever, Joshua Logan, who had directed the show on Broadway, had to battle with Jack Warner to let him film on location at real castles in Europe, while the notoriously budget-conscious producer decreed the whole production should be filmed on Warner Bros' back lot in Burbank.

In the end there was something of a compromise, with a huge set being constructed at WB Studios for interiors and much of the dramatic action, and real castles seen in wider shots.

The 'Camelot Castle' was retained after filming, to be repurposed as the 'Tibetan Lamasery' for the disastrous 1972 musical remake of Lost Horizon, and it was regularly seen in the TV series Kung Fu. It was finally torn down in the Eighties. So you won't see the castle, but you can see the famed backlot if you take the Warner Bros VIP Studio Tour (and I recommend it).

This tour, unlike the Universal Studios theme park, is the real thing – a small-scale guided tour around the surprisingly unchanged and low-tech lot. You need to book ahead, and you’ll find the tour entrance at 3400 West Riverside Drive in Burbank.

The ideal castles for location filming were eventually found, not in England, but in Spain.

The imposingly solid exterior of ' Camelot', where King Arthur (Richard Harris) attempts to establish a court based on honour and chivalry, is 15th-century Mudéjar Castillo De Coca, at Coca, a municipality in the province of Segovia, central Spain, about 30 miles northwest of the provincial capital city of Segovia itself.

It's in Segovia that you'll find 'Joyous Gard', the fortress of Lancelot (Franco Nero), which is the elegant Alcázar De Segovia, on Plaza Reina Victoria Eugenia